Automatic plate replacing apparatus for printing press

ABSTRACT

A plate replacing apparatus for a printing press having plate lockup devices for fixing the two ends of a plate located in a gap of the circumferential surface of a plate cylinder and wound around the circumferential surface includes an old plate holding mechanism and a new plate holding mechanism. The old plate holding mechanism receives and holds an old plate removed upon release of the plate lockup devices and pivotal movement of the plate cylinder. The new plate holding mechanism removes the old plate and feeds a new plate to the plate cylinder.

This is a continuation of application Ser. No. 07/941,775, filed Sep. 4,1992, now abandoned, which is a continuation of Ser. No. 07/619,120,filed Nov. 28, 1990, now abandoned.

BACKGROUND OF THE INVENTION

The present invention relates to a plate replacing apparatus forreplacing an old plate mounted on the circumferential surface of a platecylinder by a plate lockup apparatus with a new plate prepared outsidethe plate replacing apparatus.

A gap is formed along the entire length in the outer circumference ofeach plate cylinder in a printing press. A plate lockup apparatusconsisting of a leading-side lockup device for gripping the leading edgeof the plate and a trailing-side lockup device for gripping the trailingedge of the plate is fixed on the bottom surface of the gap to extend inthe axial direction of the plate cylinder.

Each of the conventional leading- and trailing-side lockup devicescomprises an elongated lockup table extending in the axial direction ofthe plate cylinder, a plurality of gripper plates, swingably supportedat an edge portion of this lockup table by a plurality of bolts, forgripping or releasing the plate with or from the lockup table, and aplurality of cams which can be respectively engaged with gaps at theedges of the gripper plates. The plurality of cams are pivotally alignedalong the axis. A plurality of compression coil springs are interposedbetween the lockup table and the gripper plates to bias the gripperplates in an open direction.

With the above arrangement, in order to mount a plate on a platecylinder, when a cam shaft of the leading-side lockup device is pivoted,the gripper plates which are divided in the axial direction of the plateare released upon disengagement from the cams and are simultaneouslyopened by the elastic forces of the compression coil springs. An end ofthe plate is inserted between the leading-side lockup device and thecorresponding lockup table. When the cam plate is pivoted in thedirection opposite to the direction described above, the gripper platesare pivoted against the elastic forces of the compression coil springsby the behavior of the cams and are closed, thereby gripping the leadingedge of the plate.

Another conventional apparatus is disclosed in Japanese Patent Laid-OpenNo. 1-127346. In this apparatus, the lockup tables and the gripperplates are disposed in the radial direction of a plate cylinder so thata trailing-side gripper surface of the plate conventionally formed inthe circumferential direction of the plate cylinder is formed in theradial direction of the plate cylinder. The edge of the plate is bent ata right angle by an external bending machine. With this arrangement,after the leading edge of the plate is gripped, the bent portion of thetrailing edge portion of the plate wound around the circumferentialsurface of the plate is inserted between the lockup tables and thegripper plates. The gripper plates are swung by a cam mechanism to gripthe bent portion of the plate. The trailing-side lockup device as awhole is circumferentially moved to uniformly mount the plate, therebybringing the plate into tight contact with the surface of the platecylinder.

In such a conventional press, when an old plate is replaced with a newplate due to changes in contents of printed matters, the trailing-sidecam shaft is pivoted to open the trailing-side lockup device. One end ofthe plate which is released from gripping is kept held, and the platecylinder is rotated. The leading-side cam shaft is pivoted to open theleading-side lockup device to release the other end of the plate fromgripping, thereby removing the old plate. Thereafter, opening/closing ofthe plate lockup devices and the pivotal operation of the plate cylinderare repeated to mount the new plate.

In plate replacement in the conventional printing press, however,pivotal movement of the cam shaft and rotation of the plate cylindermust be performed manually or upon operation of a push button. Platereplacement is cumbersome and requires skills since the old and newplates must be manually held. In addition, the new plate cannot beplaced to stand by at a mounting position of the plate cylinder duringprinting. The old plate must be removed from the press during thereplacement. A preparation period is therefore undesirably prolonged,and productivity is degraded. In addition, automatic plate replacementcannot be performed due to a requirement of plate holding.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a plate replacingapparatus for a printing press, capable of greatly shortening apreparation time, improving productivity, and reducing labor.

It is another object of the present invention to provide a platereplacing apparatus for a printing press, capable of facilitatingmaintenance and inspection and improving operability.

It is still another object of the present invention to provide a platereplacing apparatus for a printing press, capable of improving safety inoperations.

In order to achieve the above objects of the present invention, there isprovided a plate replacing apparatus for a printing press having platelockup devices for fixing the two ends of a plate located in a gap of acircumferential surface of a plate cylinder and wound around thecircumferential surface, comprising an old plate holding mechanism forreceiving and holding an old plate removed upon release of the platelockup devices and pivotal movement of the plate cylinder, and a newplate holding mechanism for removing the old plate and feeding a newplate to the plate cylinder.

At the time of plate replacement, the distal end portion of the loaderwhich holds the new plate in advance during printing is brought intocontact with the outer circumferential surface of the plate cylinder.The plate cylinder is stopped at a position where the trailing-sideplate lockup device opposes the distal end portion of the plate holdingapparatus. The leading- and trailing-side plate lockup devices areopened, and the plate cylinder is rotated by about one revolution. Theold plate is moved into the loader and is held in it. The plate cylinderis then pivoted to cause the leading-side plate lockup device to opposethe distal end portion of the loader and to push the new plate, and theplate lockup apparatus is closed to grip one end of the new plate in theleading-side plate lockup device. The plate cylinder is rotated by aboutone revolution, and the trailing-side plate lockup device is closed,thereby mounting the new plate on the plate cylinder.

According to the present invention, the loader is pivoted to bring itsdistal end portion to oppose the plate lockup device. In this case, whenthe safety bar in the safety unit is kept open, the switch is kept OFFand the loader is not pivoted. However, when the safety bar is closed,the loader is pivotal. In this case, the operator cannot enter a workingspace between the printing units due to the presence of the safety bar,thereby ensuring a safe operation.

According to the present invention, at the time of plate replacement,the loader is pivoted to be stored and suspended so that its distal endportion is separated from the plate lockup apparatus. At the time ofmaintenance and inspection of the dampening unit and supply of dampeningwater, the loader in the storage state is moved upward, so that theworking surface of the dampening unit is opened, thereby facilitatingthe operations.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 to 12H show an embodiment of a plate holding unit according tothe present invention, in which

FIG. 1 is a plan view of a plate cylinder which employs the plateholding unit,

FIG. 2 is a sectional view of the plate cylinder along the line II--IIin FIG. 1,

FIG. 3 is a sectional view of the plate cylinder along the line III--IIIin FIG. 1,

FIG. 4 is a sectional view of the plate cylinder along the line IV--IVin FIG. 1;

FIG. 5 is a sectional view of the plate cylinder along the line V--V inFIG. 1,

FIG. 6 is a longitudinal sectional view of a trailing-side plate lockupdevice before a plate is gripped,

FIG. 7 is a side view of a plate lockup opening/closing unit,

FIG. 8 is a partially cutaway side view of an upper half of the plateholding unit,

FIG. 9 is a partially cutaway side view of a lower half of the plateholding unit,

FIG. 10 is a side view showing the plate holding unit,

FIG. 11 is a side view showing the main part of a plate replacingapparatus which employs the present invention, and

FIGS. 12A to 12H are side views showing plate replacing states of theplate replacing apparatus;

FIGS. 13 to 17 show a plate replacing apparatus according to anotherembodiment of the present invention, in which

FIG. 13 is a front view of the plate replacing apparatus,

FIG. 14 is a plan view thereof,

FIG. 15 is a side view thereof along the line XIII in FIG. 13,

FIGS. 16A and 16B are an enlarged front view and a front view,respectively, of a bar distal end portion, and

FIG. 17 is a front view showing a four-color sheet fed press whichemploys the present invention; and

FIGS. 18 to 22 show a plate replacing apparatus according to stillanother embodiment of the present invention, in which

FIG. 18 is a front view of the plate replacing apparatus,

FIG. 19 is an enlarged plan view thereof along the line XIX in FIG. 18,

FIG. 20 is an enlarged side view thereof along the line IIX in FIG. 18,

FIG. 21 is an enlarged side view showing a partially cutaway sectionalong the line IIXI in FIG. 18, and

FIG. 22 is a front view of the plate replacing apparatus in a statewherein a plate holding member is kept at an upper position.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 to 12H show an embodiment in which a plate holding apparatusaccording to the present invention is employed in an automatic platereplacing apparatus.

A gap 2 having a substantially rectangular sectional shape is formed inthe outer circumferential surface of a plate cylinder 1 along the entirelength of the plate cylinder 1. Saddle-like guides 3 and 4 are bolted onthe bottom surface portions of the gap 2 at its two ends. A leading-sideplate lockup device 5 comprises a lockup table 6 having an almost squaresectional shape and extending in the axial direction of the platecylinder. Thin-walled portions 6a at the two ends of the lockup-device 6are fitted to be slightly circumferentially movable while their verticalmovement is restricted by the left and right guides 3 and 4. Anintermediate portion of the lockup table 6 is slidably pressed by aplurality of guides (not shown) fixed on the bottom surface of the gap2, so that floating of the lockup table 6 is prevented. A plurality ofscrew holes 6b are formed in portions along the longitudinal directionof the lockup table 6 and each has a section shown in FIG. 4. Anadjusting screw 7 whose distal end is tapered is threadably engaged witha corresponding one of the screw holes 6b. A collared pin 8, the collarportion of which is fitted between the lockup table 6 and the gap 2, isslidably inserted in each pin hole corresponding to each of theadjusting screws 7. The distal end of the collared pin 8 abuts against atapered surface of the corresponding adjusting screw 7. With thisarrangement, when the adjusting screw 7 is turned, the lockup table 6 isslightly moved in the circumferential direction by the behavior of thetapered surface. A compression coil spring 9 in FIG. 5 is insertedbetween a stud 10 on the lockup table 6 and the wall surface of arecessed hole 2a of the gap 2 to bias the lockup device 5 outward.

An L-shaped leading-side plate holder 11 shown in FIG. 5 is fixed bybolts 12 and 13 on the inclined surface of the lockup table 6. Threegripper plates 14 having a substantially V-shaped section, divided inthe axial direction of the plate cylinder, and constituting the sameoverall length as that of the lockup table 6 are swingably supported onpins 11a horizontally extending from the plate holders 11. A grippersurface 14a of each gripper plate 14 opposes the gripper surface of thelockup table 6. Although not shown, a plurality of projections areformed on the gripper surface 14a and are engaged with the recessesformed in the opposite gripper surface. A plurality of studs 15 eachhaving a sectional shape shown in FIG. 2 extend upward from the bottomsurface of the lockup table 6 and are aligned in the axial direction ofthe plate cylinder to extend into the recessed hole 2a of the gap 2. Acompression coil spring 17 is inserted between a spring reception pin 16threadably engaged with a screw hole of each stud 15 and the gripperplate 14 to bias the gripper plate 14 in a direction so that the grippersurface 14a of the gripper plate 14 is closed.

A plurality of bearings 18 having a rectangular parallelepiped shape arefixed by bolts at the central part of the bottom surface of the gap 2and are aligned along the axial direction of the plate cylinder. Ahexagonal cam shaft 19 is fitted in the bearings 18. A plurality ofplate gripper cams 20 each having large- and small-diameter portions aremounted on the cam shaft 19 in tandem with each other. The cam surfaceof each plate gripper cam 20 is in contact with a vertical surface ofthe corresponding gripper plate 14. Upon driving of the cam shaft 19 bya drive unit (to be described later), the large-diameter portions of theplate gripper cams 20 cause the gripper plates 14 to pivot in thecounterclockwise direction against the biasing forces of the compressioncoil springs 17, so that the gripper surfaces 14a are opened.

A Trailing-side plate lockup device 30 is arranged parallel to theleading-side lockup device 5 within the gap 2. The trailing-end lockupdevice 30 comprises a spring reception bar 31 having almost the samelength as the overall length of the plate cylinder and a verticalsurface which is in contact with the vertical surface of thecorresponding bearing 18. The spring reception bar 31 is fixed on thebottom surface of the gap 2 by a plurality of bolts 32. The springreception bar 31 comprises a regulation surface 31a extending in theradial direction of the plate cylinder 1. A support shaft 33 extendsbetween the regulation surface 31a and a wall surface 2b of the gap 2 sothat the two ends of the support shaft 33 are located near disc bearers34 at the two ends of the plate cylinder 1. Three separated lockup tales35 and three separating gripper plates 36 have opposite gripper surfaces35a and 36a extending in the radial direction of the plate cylinder 1 sothat ends of the lockup tables 35 and the gripper plates 36 opposite tothese gripper portions are swingably connected to each other through thesupport shaft 33. Reference numerals 37 denote adjusting screws forconnecting the three separated lockup tables 35. Right- and left-handthreads are threadably engaged with screw holes of each lockup table 35.A tool is inserted into a hole of a collar portion 37a integrally formedbetween the two adjacent lockup tables 35 and is turned to adjust adistance between the adjacent lockup tables 35.

A rod-like cam 38 formed by a planar small-diameter portion 38a and anarcuated large-diameter portion 38b is pivotally mounted on the bearer34 in a recessed portion 2c formed in the wall surface 2b of the gap 2.An extended portion 38c of the cam 38 from the bearer 34 has a hexagonalshape. Reference numeral 40 denotes a guide for pivoting the cam 38 andis fixed in the recessed portion 2c of the wall surface 2b by a bolt 41.Compression coil springs 42 are interposed between a plurality of springhole bottom surfaces formed in the non-gripper ends of the lockup tables35 and the plurality of spring hole bottom surfaces formed in the springreception bar 31 to separate the lockup tables 35 from the springreception bar 31. A compression coil spring 45 is interposed between thebottom surface of a spring hole 31b and a collar portion of a springshaft 44 whose movement is limited by a double nut 43 slidably mountedin the spring hole 31b of the upper portion of the spring reception bar31, and separates each gripper plate 36 from the spring reception bar31. A compression coil spring 46 is arranged within the spring hole ofthe upper portion of each lockup table 35 to bias this lockup table 35from the corresponding gripper plate 36. Reference numeral 47 denotes ablanket cylinder which is brought into rolling contact with the platecylinder 1.

An opening/closing drive unit for pivoting the cam shaft 19 and the cam38 to open/close each plate gripper surface will be described below.Each opening/closing drive unit is arranged near each of right and leftframes 50 for supporting the plate cylinder 1 and the blanket cylinder47. The right drive unit (the left-hand unit in FIG. 1 for illustrativeconvenience) on the right frame 50 when viewed from the sheet feederwill be described first. An air cylinder 51 serving as a drive unit isswingably supported on the upper end face of the frame 50 through abracket 52. Levers 53 and 54 are split-fixed on the leading-side camshaft 19 and the trailing side cam 38 between the bearer 34 and theframe 50. A link mechanism 55 is arranged between the air cylinder 51and the levers 53 and 54. The distal end portion of a rod 57 connectedto a piston rod 56 of the air cylinder 51 is connected to a free endportion of an L-shaped lever 59 pivotally supported on the upper surfaceof the frame 50 through a bracket 58. The lower end portion of a rod 60whose upper end is connected to the other free end portion of theL-shaped lever 59 is connected to a free end portion of a lever 62supported on a stud 61 of the frame 50. A lever 63 is formed integrallywith the lever 62. A free end portion of the lever 63 is connected toone end of a roller lever 64. Reference numeral 65 denotes a lever shaftpivotally supported between the right and left frames so that axialmovement of a lever 66 pivotally mounted thereon is limited. A free endportion of the lever 66 is supported by the central portion of theroller lever 64. That is, a four-joint link is constituted by the levers63 and 66 and the roller lever 64. When the lever 62 is driven by theair cylinder 51 and is swung, the roller lever 64 is reciprocatedtogether with the levers 63 and 66 in the radial direction of the platecylinder 1. A roller 67 which is selectively brought into contact withthe lever 53 or 54 in accordance with a pivotal phase of the platecylinder 1 is mounted on the distal end portion of the roller lever 64.When the roller lever 64 is reciprocated, the lever 53 or 54 is pivotedabout the cam shaft 19 or the cam 38 within the range between the solidline and the alternate long and short dashed line in FIG. 7.

In the right opening/closing drive unit, when the lever 53 is located atthe position indicated by the solid line, the plate gripper surfaces ofthe leading-side lockup device 5 are closed. However, when the lever 54is located at the position indicated by the solid line, the plategripper surfaces of the trailing-side lockup device 30 are open.

The left opening/closing drive unit (the right drive unit in FIG. 1) onthe left frame side when viewed from the sheet feeder is arrangedsimilarly to the right opening/closing drive unit, although the leftopening/closing drive unit is not illustrated in FIG. 7. The arrangementof the left opening/closing drive unit is the same as that of the rightopening/closing drive unit as far as the components from the aircylinder 51 to the roller 67 are concerned. The arrangement of the leftopening/closing drive unit is different from that of the rightopening/closing drive unit in levers 53 and 54. That is, as shown inFIGS. 1 and 7, the right levers 53 and 54 extend upward from the camshaft 19 and the cam 38. However, in the left opening/closing driveunit, levers 53A and 54A in FIG. 1 extend downward from the cam shaft 19and the cam 38. That is, the distal end portion of the righttrailing-side lever 54 and the distal end portion of the leftleading-side lever 53A are in phase in the circumferential direction andoppose the rollers 67. With this arrangement, when the right and leftair cylinders 51 are simultaneously actuated, the lever 54 is pressed bythe right roller 67 to open the plate gripper surfaces of thetrailing-side plate lockup device 30. At the same time, the left lever53A is pressed by the left roller 67. At the same time, the right lever54 is moved from the position of the solid line to the position of thealternate long and short dashed line, so that the plate gripper surfacesof the leading-side plate lockup device 5 are opened.

Reference numeral 70 in FIG. 11 denotes a cover for covering the frontside of the plate cylinder 1 throughout its entire length. The cover 70is pivotally supported on a free end portion of an L-shaped lever 72pivotally supported on the upper end surface of the frame 50 through abracket 71. An actuation end of a piston rod 74 of an air cylinder 73pivotally supported on the frame 50 is mounted on the L-shaped lever 72.With this arrangement, when the air cylinder 73 is actuated in responseto a command from a control unit, the cover 71 is moved in the range ofthe position indicated by the solid line and the position indicated bythe alternate long and short dashed line.

A plate replacing apparatus for replacing an oil plate with a new plateis arranged in the plate lockup apparatus and the opening/closing unit.That is, a pair of right and left brackets 81 are located obliquelyabove the plate cylinder 1 and are mounted on the upper ends of the rearsides of right and left frames 80 mounted in a printing unit in front ofthe frames 50. The proximal end of a loader 83 serving as a plateholding member having a rectangular member whose long sides are alignedin the horizontal direction and having almost the same length as theplate cylinder is mounted on a support shaft 82 pivotally mounted onthese brackets 81. An air cylinder 84 connected to the control unit ispivotally supported on the right and left frames 80 near the brackets81. A lever 86 supported by the frame 80 and a lever 87 supported on theloader 83 are connected to an actuation end of a piston rod 85 of theair cylinder 84. With this arrangement, when the piston rod 85 of theair cylinder 84 is reciprocated, the loader 83 is swung through thelevers 86 and 87 between a suspended position indicated by the solidline and an inclined position indicated by the alternate long and shortdashed line, so that the distal end portion of the loader 83 comes closeto or is separated from the circumferential surface of the platecylinder 1.

As shown in FIG. 9, two guide plates 88 having a V-shaped inletvertically extend in the lower half of the loader 83. When the platelockup device 30 is opened, a plate 89 released and rewound upon pivotalmovement of the plate cylinder 1 is inserted between the guide plates 88in a direction indicated by an arrow. A plurality of pairs of brackets90 each having an oval shape are fixed on the tubular support shaft 82in the upper end portion of the loader 83 at positions obtained bydividing the overall width of the loader 83 into 1/3. Convex members 91are supported on the respective pairs of brackets 90. Each convex member91 has a band-like leaf spring 92 biased in a direction to wind theconvex 91. The fixed end of the leaf spring 92 is fixed to a platetrailing edge holding unit 93. An L-shaped plate hook 95 which is heldin an upright position (position of the solid line) by a biasing forceof a coil spring 96 is pivotally supported in a holder 94 at the end ofthe leaf spring 92. A bent portion of the plate 89 entering between theguide plates 88 is hooked by a hook portion of the plate hook 95. Thatis, prior to the start of replacement of the plate 89, the platetrailing edge holding unit 93 is manually moved downward to the centralstandby position of the loader 83, and a piston rod 98 of an aircylinder 97 arranged at this standby position is moved forward upondepression of a push button. The plate hook 95 is open to be located atthe position of the alternate long and short dashed line against thebiasing force of the torsion coil spring 96. When the holder 94 is urgedagainst a cover 99 by the upper end of the plate hook 95, the platetrailing edge holding unit 93 as a whole is prevented from upwardmovement against the tension of the leaf spring 92. Reference numeral100 denotes a sensor consisting of a light-emitting element and alight-receiving element and located near the air cylinder 97. The sensor100 detects the leading edge of the plate 89 entering between the guideplates 88, and the piston rod 98 of the air cylinder 97 is movedbackward to cause the plate hook 95 to stand against the elastic forceof the torsion coil spring 96. The bent portion of the plate 89 ishooked by the plate hook 95, and at the same time, locking by the holder94 is released, so that the plate trailing edge holding unit 83 as awhole is moved upward together with the plate 89 by the tension of theleaf spring 92. Therefore, the plate 89 is pulled into the loader 83. Apin 102 is slidably supported in a hole of a block 101 arranged incorrespondence with the plate hook 95 at the upper end portion of theloader 83 and is biased in a direction to be removed from the block 101by a compression coil spring 103. This pin 102 is pushed against theelastic force of the compression coil spring 103 to incline the upperend portion of the plate hook 95 as indicated by the alternate long andshort dashed line, thereby releasing the bent portion of the plate 89.Therefore, the plate 89 can be removed from the loader 83.

A plate feed unit will be described below. Upper-, middle- (not shown),and lower-stage suction pads 104 (each stage consists of a plurality ofpads) for chucking a new plate 105 to be fed to the plate cylinder 1 inplace of the old plate 89 are connected to a suction air source and arearranged on the surface of the loader 83. The lower-stage suction pads104 are vertically movable. That is, a pair of right and left aircylinders 106 are supported on both side plates of the loader 83 throughbrackets 107 above the lower-stage suction pads 104. The suction pads104 are mounted in tandem with each other on a bar 109, both ends ofwhich are fixed to piston rods 108 of the air cylinders 106. When thepiston rods 108 are moved forward, the bar 109 which holds the new plate105 is moved from a position indicated by the solid line to a positionindicated by the alternate long and short dashed line, so that the newplate 105 is fed to the leading-side lockup device 5 which is open tothe leading edge of the new plate 105. Reference numerals 110 denoteracks fixed on the right and left side plates of the loader 83 andmeshed with pinions 111 at the two ends of the bar 109 to smoothly movethe bar 109 backward. Reference numeral 112 denotes a reference pinslidably fitted in a hole of another bar 113 and biased by a compressioncoil spring 114 to extend to be fitted in a reference hole of the newplate 105, thereby positioning the new plate 105.

Roller arms 116 are fixed at both side portions of an arm shaft 115extending from the loader 83 at the lower end portion of the loader 83,while the arm shaft 115 is pivotally supported. A plurality ofbrush-like rollers 118 are pivotally mounted in tandem with each otheron a roller shaft 117 supported between the free end portions of thearms 116. A lever 123 is fixed through a connecting plate 122 to theactuation end of a piston rod 121 of an air cylinder 120 fixed to onewidthwise end of the loader 83 through a bracket 119. The free endportion of a lever 124 fixed on the arm shaft 115 is mounted on thelower end portion of the lever 123. With this arrangement, when thepiston rod 121 of the air cylinder 120 is reciprocated, the arm 116 canbe pivoted in the range between a storage position indicated by thesolid line in FIG. 9 and an in-operation position indicated by thealternate long and short dashed line. In the in-operation position, theroller 118 is brought into tight contact with the new plate 105 on theplate cylinder 1, and the inner surface of the plate 105 is brought intotight contact with the outer circumferential surface of the platecylinder 1. At the same time, the bent portion of the trailing edge ofthe new plate 105 is inserted into the open trailing-side lockup device30. A plurality of brush-like rollers 125 are arranged in tandem witheach other on the arm shaft 115 and are brought into slidable contactwith the new plate 105 so as to guide it to the plate lockup device 5.Reference numerals 126 denote form rollers (generally at least fourrollers) of an inking apparatus brought into contact with the platesurface on the plate cylinder 1 to apply an ink to the plate surface.

The units and apparatuses described above and a servo motor for rotatingthe plate cylinder 1 are connected through a control unit (not shown)and are operated at predetermined timings.

An operation of the plate replacing apparatus having the plate holdingunit will be described below. During printing, as shown in FIG. 12A, theloader 83 is suspended from the support shaft 82. In this state, the newplate 105 is chucked by the upper-, middle-, and lower-stage suctionpads 104, and the reference pin 112 is fitted in the reference hole, sothat the new plate 105 is positioned and mounted in the loader 83. Theplate trailing edge holding unit 93 in the loader 83 is manually moveddownward. When the air cylinder 97 is operated with the push button, thepiston rod 98 is moved forward to urge the plate hook 95. The plate hook95 is inclined as indicated by the alternate long and short dashed linein FIG. 8 and is thus opened.

When printing is completed and the old plate 89 is to be replaced withthe new plate 105, a start button is depressed. The air cylinder 73 isactuated to open the cover 70 through the L-shaped lever 72, asindicated by the alternate long and short dashed line in FIG. 11. At thesame time, the air cylinder 84 is actuated to incline the loader 83 to aplate replacement position of FIG. 12B, through the levers 86 and 87. Inthis case, as shown in FIGS. 12C and 9, the trailing-side lockup device30 opposes the distal end portion of the loader 83. At the same time, asshown in FIG. 7, the right roller 67 opposes the distal end portion ofthe lever 54 on the cam 38. The left roller 67 opposes the lever 53A onthe cam shaft 19 which is in phase with the lever 54. In this state,when the right and left air cylinders 51 are simultaneously actuated,the leading- and trailing-side lockup devices 5 and 30 aresimultaneously opened upon rotation of the cam 38 and the cam shaft 19.

In this state, the trailing edge portion of the old plate 89 is poppedup by its rigidity from the trailing-side lockup device 30 and abutsagainst a guide 130, as shown in FIG. 12C. The plate cylinder 1 ispivoted in a direction opposite to the direction of the arrow in FIG. 9,so that the trailing edge of the old plate 89 is inserted between theguide plates 88 of the loader 83. When the inserted old plate 89 passesthrough the sensor 100, the sensor 100 detects the plate and drives theair cylinder 97, so that the piston rod 98 is moved backward. The platehook 95 then stands up, as indicated by the solid line in FIG. 8. As aresult, the plate hook 95 hooks the trailing-edge bent portion of theold plate 89, locking of the holder 94 is released, and the platetrailing-edge holding unit 93 as a whole is moved upward by a tensionaccumulated by each leaf spring 92 arranged on the corresponding convexmember 91. The old plate 89 held on the plate hook 95 is pulled andstored into the loader 83. FIG. 12D shows a state during removal of theold plate 89.

When the plate removal is completed, the servo motor is operated toslightly pivot the plate cylinder 1, and the plate cylinder 1 is stoppedso that the open plate gripper surface of the leading-side lockup device5 reaches a line extended from the new plate 105 and held on the loader83, as shown in FIG. 9. At the same time, the air cylinder 106 isactuated to rotate the pinions 111 on the racks 110, so that the bar 109is moved downward. The new plate 105 held by the lower-stage suctionpads 104 is guided in slidable contact with the rollers 125. The leadingedge of the new plate 105 is inserted into the leading-side lockupdevice 5. At this time, the lever 53 shown in FIG. 7 is located at theposition of the alternate long and short dashed line and opposes theroller 67. When the air cylinder 51 is actuated, the cam shaft 19 isrotated together with the lever 53 to close the leading-side lockupdevice 5, and the new plate 105 is gripped by the leading-side lockupdevice 5. This state is shown in FIG. 12E.

When the servo motor is operated in this state to pivot the platecylinder 1 in the direction of the arrow, the new plate 105 is woundaround the circumferential surface of the plate cylinder 1, and thetrailing edge of the new plate 105 is stopped at a positioncorresponding to the roller 118. Thereafter, the air cylinder 120 isactuated to move the piston rod 121 backward. The arm 116 is pivotedthrough the levers 123 and 124, and the brush-like rollers 118 arebrought into tight contact with the circumferential surface of the platecylinder 1, thereby inserting the trailing-edge bent portion of the newplate 105 into the trailing-side lockup device 30 by the rollers 118.During rotation of the plate cylinder 1, the rollers 125 are rotated inrolling contact with the surface of the new plate 105. Therefore, thenew plate 105 is brought into tight contact with the circumferentialsurface of the plate cylinder 1. FIG. 12F shows a state during rotationof the plate cylinder 1. FIG. 12G shows a state after rotation. When thetrailing-edge end portion of the new plate 105 is inserted into thetrailing-side plate lockup device 30, the left air cylinder is operated.In this case, the lever 54 has already been returned to the positionindicated by reference numeral 54A. The roller urges the lever 54Adownward, and the pivotal movement of the cam 38 causes closing of thetrailing-side plate lockup device 30, thereby gripping the inserted endof the new plate 105. At the end of pivotal movement of the cam 38, thegripper plates 36 and the lockup tables 35 become integral with eachother and move together in the circumferential direction of the platecylinder 1. The new plate 105 is thus kept taut and is brought intotight contact with the circumferential surface of the plate cylinder 1.

The piston rod 85 of the air cylinder 84 is moved backward to pull thelevers 86 and 87. The loader 83 is moved downward to the stored state,as shown in FIG. 12H. The cover 70 is covered upon operation of the aircylinder 73. Therefore, printing can be restarted.

After printing is restarted, when the pin 102 is pushed at the frontside of the loader 83 at a proper timing, the plate hook 95 is inclinedto release the old plate 89. The old plate 89 is removed from the loader83. As described above, the new plate 105 can be mounted on the loader83 to stand by. A space between the printing units is not reduced in thestored state of the loader 83.

FIGS. 13 to 17 show a plate replacing apparatus according to anotherembodiment of the present invention.

Members except for those of a safety unit in FIGS. 13 to 17 areidentical to those in FIGS. 1 to 12H. The same reference numerals denotethe same parts throughout these drawings, and a detailed descriptionthereof will be omitted.

Referring to FIGS. 13 to 17, a printing press 201 comprises a paper feedunit 203 having a paper stacker for stacking sheets 202 thereon and apaper feeder for feeding the sheets 202 one by one, and a delivery unit205 having a stack board for stacking printed matters printed by eachprinting unit 204. Each printing unit 204 has printing cylinders (e.g.,a plate cylinder 1 and a blanket cylinder 47), an inking unit, and adampening unit.

A safety unit is arranged in the plate replacing apparatus to protect anoperator from a loader 83. L-shaped brackets 230 are fixed on right andleft frames 50 of each of the printing units 204 at positionssubstantially the same height as that of the axis of the plate cylinder1 so as to oppose the side on which the loader 83 is mounted. A supportshaft 232 is pivotally supported on the brackets 230 so that axialmovement of the support shaft 232 is restricted by collars 231. Eachsafety bar 233 having a rod-like shape and almost the same lengthcorresponding to a distance between the adjacent frames 50 is disposedat the extended end portion of the corresponding support shaft 232extending from the bracket 230. The safety bar 233 is pivoted togetherwith the corresponding support shaft 232 to be horizontal to close aspace of the printing press between the frames 50. However, when thesafety bar 233 is pivoted and stands upright, the space is released.Reference numeral 234 denotes a pin extending on the corresponding frame50 and fitting in a groove of the corresponding safety bar 233 tohorizontally fix the safety bar 233. Reference numeral 235 denotes aholder fixed on the frame 50 to clamp and hold the safety bar 233upright. A cam 236, the circumferential surface of which is partiallychamfered, is integrally fixed on the corresponding support shaft 232. Alimit-switch 237 connected in series with an air cylinder 84 for drivingthe loader 83 is arranged to oppose the cam 236. As a result, when thesafety bar 233 is set horizontal, the chamfered portion of the cam 236opposes the contact to turn on the limit switch 237, thereby actuatingthe air cylinder 84. When the safety bar 233 stands upright, an arcuatedportion of the cam 236 opposes the contact. In this case, the limitswitch 237 is turned off, and the air cylinder 84 is disabled.

An operation of the plate replacing apparatus having the above structurewill be described below. During printing, the loader 83 is suspendedfrom a swing shaft 82 and is stored. In this state, the safety bar 233stands upright and is clamped by the holder 235. The arcuated portion ofthe cam 236 is kept in contact with the contact of the limit switch237,.and the air cylinder 84 is kept disabled. During the printingoperation, the operator enters the space between the printing units tohold a new plate in the loader 83. The loader 83 is not accidentallypivoted, thus ensuring a safe operation. Upon completion of printing,when the old plate is to be replaced with a new one, the safety bar 233is held horizontal and is fixed by the pin 234 to enable the aircylinder 84. When a start button is depressed, each air cylinder isoperated to open a cover 70 in the illustrated manner. The air cylinder84 is actuated to incline the loader 83 toward the plate replacingapparatus through levers 86 and 87. The servo motor is rotated by apredetermined angle until the plate cylinder 1 is located to the platedischarge position. When right and left air cylinders 51 aresimultaneously actuated, the gripper surfaces of the trailing-sidelockup device 5 are opened, and at the same time, the gripper surfacesof the leading-side lockup device 30 are also opened. The plate releasedfrom the lockup devices is released into a loader 83A upon pivotalmovement of the plate cylinder 1 and the operation of the delivery unitin the loader 83A. A new plate is mounted on the plate cylinder 1 bypivotal movement of the plate cylinder 1, opening/closing of the platelockup apparatus, and the operation of the plate feed unit in the loader83A. During plate replacement, since the safety bar 233 is heldhorizontal and closes the space between the printing units, the operatorcannot enter this space, thus ensuring a safe operation. Upon completionof plate replacement, the loader 83A is suspended, and the safety bar233 is opened. The air cylinder 84 is set disabled. The operator entersthe space between the printing units and removes the old plate from theloader 83. The next plate is held in the loader 83. In this case, theloader 83 is not accidentally pivoted, thus ensuring a safety operation.

In this embodiment, the safety bar is pivotally arranged and is actuallypivoted to open/close the working space between the printing units.However, the safety bar may be axially reciprocated to open/close thespace. In this embodiment, the plate holding member holds the old andnew plates. However, the plate holding member may hold one of the oldand new plates.

FIGS. 18 to 22 show a plate replacing apparatus according to stillanother embodiment of the present invention. The arrangement of theplate replacing apparatus of this embodiment is substantially the sameas that of the above embodiment except for a support structure for aplate holding member. The same reference numerals as in FIGS. 1 to 17denote the same parts in FIGS. 18 to 22, and a detailed description ofthereof will be omitted.

Referring to FIGS. 18 to 22, each printing unit 302 comprises an inkingunit (not shown), a dampening water unit 307 consisting of a water pan305 and rollers 306. A pair of right and left rectangular parallelepipedbrackets 309 are fixed on the upper end faces of frames 50 obliquelyabove a plate cylinder 1. U-shaped bearing grooves 309a open upward areformed in these brackets 309. A loader 83 serving as a plate holdingmember having a rectangular shape with a length almost equal to theaxial length of the plate cylinder 1 is swingably arranged in thebearing grooves 309a through roller bearings 311. The roller bearings311 are pivotally mounted on the proximal portion of the loader 83 so asto be vertically detachable. Air cylinders 84 connected to a controlunit are swingably supported on the right and left frames 50 near thebrackets 309. A lever 86 pivoted on the frame 50 and a lever 87 pivotedon the loader 83 are connected to the actuation end of a piston rod 85.When the piston rod 85 of the air cylinder 84 is reciprocated, theloader 83 is swung through the levers 86 and 87. More specifically, theloader 83 is swung between a suspended position representing a storedposition indicated by reference numeral 83B and an inclined positionindicated by reference numeral 83A, so that the distal end portion ofthe loader 83 is moved to come close to or to be separated from thecircumferential surface of the plate cylinder 1. An old plate holdingunit is arranged inside the loader 83 to incline the loader 83 to theposition indicated by reference numeral 83A to perform opening/closingof the plate lockup devices and pivotal movement of the platecylinder 1. The unnecessary old plate removed from the plate cylinder 1enters a loader 83A and is held therein. A plate feed unit is arrangedinside the loader 83A, and the new plate held within the loader 83A ismounted on the plate cylinder 1 in an order opposite to that of plateremoval.

An apparatus for moving the loader 83 upward to open the working surfaceof the dampening unit 307 is arranged in the plate replacing apparatus.The proximal end portions of gas springs 316 serving as spring membershaving large strokes are pivotally supported on the right and leftframes 50 of each printing unit 302 through brackets 317 fixed near theupper end portions of the dampening unit 307. The upper end portion ofthe gas spring 316 is pivotally mounted on the loader 83 through anL-shaped metal piece 318. With this arrangement, the loader 83 is keptbiased upward by the gas spring 316 so that a state shown in FIG. 22 isan upper limit. Upon movement of the loader 83 to the upper limit, theworking surface of the dampening unit 307 is entirely opened. Referencenumeral 319 denotes a stop lever pivotally supported on the upper endface of the bracket 309 and can be pivoted between the solid line andthe alternate long and short dashed line in FIG. 19. When the stop lever319 is pivoted to the position indicated by the solid line while theloader 83 is moved downward against the elastic force of the gas spring316, upward movement of the loader 83 is prevented. Reference numeral320 denotes a guide roller which is pivotally fitted at the distal endportion of a pin 321 extending from the bracket 309 and is brought intorolling contact with the loader 83, thereby vertically guiding theloader 83. Reference numeral 322 denotes a guide extending from thebracket 9 to vertically guide the gas spring 316. A bearing 323 shown inFIG. 21 is fixed to a pivot portion of a lever 315 on the side of theloader 83. An L-shaped pin 325 biased toward a lever 315 by acompression coil spring 324 is axially supported within this bearing323. The distal end portion of the pin 325 is detachably inserted intothe pin hole of the lever 315. With this arrangement, when the pin 325is removed from the pin hole of the lever 87 against the elastic forceof the compression coil spring 324, the loader 83 can be verticallymoved. A limit switch 326 connected to a control unit is supported onthe bracket 309 near the roller bearing 311 of the loader 83 located inthe stored state. The printing press can be operated only when theloader 83 is kept at the lower position.

An operation of the plate replacing apparatus having the abovearrangement will be described below. During printing, the loader 83 iskept suspended in a stored state while the bearings 311 are fitted inthe bearings 309a of the brackets 309, as indicated by referencenumerals 83A and 83B. Upward movement of the loader 83 is prevented bythe stop lever 319.

When the old plate is to be replaced with a new plate upon completion ofprinting, and when a start button is depressed, the loader 83 isinclined to the plate replacement position indicated by referencenumeral 83A in FIG. 18 through the levers 86 and 87 upon actuation ofthe air cylinder 84. The servo motor is rotated to pivot the platecylinder by a predetermined angle so as to locate it to the plateremoval position. At this time, the right and left air cylinders aresimultaneously actuated, and the plate gripping surfaces of thetrailing-side lockup device are open. The plate released from thisgripping is removed into the loader 83A upon pivotal movement of theplate cylinder and the actuation of the plate removal unit in the loader83A. The new plate held in the loader 83A beforehand is mounted on theplate cylinder by pivotal movement of the plate cylinder,opening/closing of the plate lockup devices, and the operation of thepaper delivery unit in the loader 83A. Upon completion of platereplacement, the loader 83A is set suspended, and the operator entersthe space between the printing units. The old plate in the loader 83 isremoved, and the next plate is held in the loader.

When the dampening unit 307 is subjected to maintenance or inspection,or when dampening water is supplied to the water pan 305, the pin 325 ispulled in the direction of the arrow in FIG. 21 to disengage the lever87 from the loader 83. The stop lever 319 is pivoted to the positionindicated by the alternate long and short dashed line in FIG. 19. Theloader 83 is then released from the stop lever 319, so that the loader83 is moved upward to the illustrated position in FIG. 22 while beingguided by the guide roller 320 and the guide 322. As a result, theworking surface of the dampening unit 307 is entirely opened.

In the above embodiment, the plate holding member holds both the old andnew plates. However, the plate holding member may hold either the new orold plate. In addition, the spring member for moving the plate holdingmember upward and the member for holding the plate holding member to thelower position and preventing it from moving upward need not bearranged.

A plate replacing apparatus for a printing press according to thepresent invention, as has been described above, comprises an old plateholding mechanism for receiving and holding an old plate removed uponrelease of the plate fixing unit and rotation of the plate cylinder, anda new plate holding mechanism for replacing the old plate with a newplate and holding the new plate supplied to the plate cylinder. The newplate can be placed to stand by and the old plate can be removed fromthe plate cylinder during a time interval except for the platereplacement time. The preparation time can be greatly shortened, andproductivity can be improved. At the same time, the plate need not bemanually held, thereby reducing the labor. The plate holding apparatusis swingably supported about a printing press fulcrum located obliquelyabove the plate cylinder so that the distal end portion of the plateholding unit can be moved to come close to or to be separated from thecircumferential surface of the plate cylinder. The same space as in thecase wherein the plate holding unit is not arranged can be assuredbetween the adjacent printing units. Plate replacement, inkreplenishment, and maintenance operations can be facilitated, andworkability is not degraded.

In the present invention, a plate holding member is arranged to bedriven by an actuator between an actuation position wherein the distalend of the unit comes close to the plate lockup device and a storedposition wherein the distal end is separated from the plate lockupdevice. A safety bar is arranged to cross and close the space formedbetween the printing units, and a series-connected switch is arrangedbetween the safety bar and the actuator. Automatic plate replacementbetween the old and new plates can be facilitated, and energy saving canbe achieved. The preparation time can be shorted to improve theproductivity. At the same time, when the safety bar in the safety unitis open, the switch is turned off to prevent pivotal movement of theloader. However, when the safety bar is closed, the loader is pivoted.In this case, the operator cannot enter the space between the printingunits due to the presence of the safety bar, thereby improving thesafety in operation.

According to the present invention, a plate holding member is arrangedto be movable toward the printing press and vertically movable betweenthe actuation position where the distal end portion comes close to theplate lockup device and the stored position where the distal end portionis separated from the plate lockup device. Plate replacement between theold and new plates can be easily automated, and energy saving isachieved. The preparation time can be shortened to improve theproductivity. Since the plate holding member is moved upward to entirelyopen the working surface of the dampening unit, maintenance andinspection of the dampening unit, supply of dampening water to the waterpan, and replacement of rollers can be facilitated, thereby improvingworkability and safety.

What is claimed is:
 1. An automatic plate replacing apparatus whichreplaces an old plate with a new plate in a printing unit of a printingpress, the printing press having a frame which supports the contents ofleast one printing unit, the printing unit having a plate cylinder witha circumferential surface having plate lockup devices disposed within agap of the circumferential surface for engaging a plate wound around thecircumferential surface, the automatic plate replacing apparatuscomprising:a loader arm, with a proximate end and a distal end, theproximate end coupled to the frame by a fulcrum, the fulcrum disposedobliquely above the plate cylinder so that the distal end of the loaderarm is separated from the circumferential surface of the plate cylinder;an old plate holding mechanism using the loader arm for receiving andholding the old plate disengaged from the plate lockup devices in thecircumferential surface of the plate cylinder; a new plate holdingmechanism using the loader arm for holding and feeding the new plate tothe plate lockup devices in the circumferential surface of the platecylinder; an actuator means coupled between the frame and the loader armfor moving the loader arm between a stored position, where the loaderarm is separated from the circumferential surface of the plate cylinderand an actuation position, where the loader arm is proximate to thecircumferential surface of the plate cylinder; a plate replacement unitcoupled to the frame and to the printing unit integrating the old plateholding mechanism with the new plate holding mechanism so that the platereplacement unit operates the old plate holding mechanism and the newplate holding mechanism while the loader arm continuously maintains theactuation position.
 2. An apparatus according to claim 1, wherein theplate replacement unit moves upward from the frame of the printing presswhile the loader arm is in the stored position, where the loader arm isseparated from the circumferential surface of the plate cylinder.
 3. Anautomatic plate replacing apparatus which replaces an old plate with anew plate for each of several printing units of a printing press, eachprinting unit having a frame which supports the components of a printingunit, a plate cylinder with a circumferential surface having platelockup devices disposed within a gap of the circumferential surface forengaging a plate wound around the circumferential surface, the automaticplate replacing apparatus for a first printing unit of several printingunits comprising:a loader arm, with a proximate end and a distal end,the proximate end coupled to the frame of the first printing unit by afulcrum, the fulcrum disposed obliquely above the plate cylinder so thatthe distal end of the loader arm is separated from the circumferentialsurface of a plate cylinder of a second printing unit of severalprinting units adjacent to the first printing unit; an old plate holdingmechanism using the loader arm for receiving and holding the old platedisengaged from plate lockup devices in the circumferential surface ofthe plate cylinder of the second printing unit; a new plate holdingmechanism using the loader arm for holding and feeding the new plate tothe plate lockup devices in the circumferential surface of the platecylinder of the second printing unit; an actuator means coupled betweenthe frame of the first printing unit and the loader arm of the firstprinting unit for moving the loader arm between a stored position, wherethe loader arm is separated from the circumferential surface of theplate cylinder of the second printing unit, and an actuation position,where the loader arm is proximate to the circumferential surface of theplate cylinder of the second printing unit; a plate replacement unitcoupled to the frame of the second printing unit integrating the oldplate holding mechanism with the new plate holding mechanism so that theplate replacement unit operates the old plate holding mechanism and thenew plate holding mechanism while the loader arm continuously maintainsthe actuation position.
 4. An apparatus according to claim 3, whereinthe plate replacement unit moves upward away from the frame of theprinting unit while the loader arm is in the stored position, where theloader arm is separated from the circumferential surface of the platecylinder.
 5. An apparatus according to claim 3, wherein the platereplacement unit crosses a working space disposed between the frames ofadjacent printing units during movement of the loader arm by theactuator means, the printing press further comprising a safety barcoupled to the frame of each of several printing units for crossing andclosing the working space, the safety bar movable between an openposition where an operator can enter the working space and a closedposition where the operator cannot enter the working space; anda switchwhich inhibits the plate replacement unit from crossing the workingspace when the safety bar is in the open position.
 6. An automatic platereplacing apparatus which replaces an old plate with a new plate foreach of several printing units of a printing press, the printing presshaving a frame which supports the components of at least two adjacentprinting units, the adjacent printing units each having a plate cylinderwith a circumferential surface having plate lockup devices disposedwithin a gap of the circumferential surface for engaging a plate woundaround the circumferential surface, the automatic plate replacingapparatus comprising:a loader arm, with a proximate end and a distalend, the proximate end coupled to the frame of one of the at least twoadjacent printing units by a fulcrum, the fulcrum disposed obliquelyabove the plate cylinder so that the distal end of the loader arm isseparated from the circumferential surface of the plate cylinder; an oldplate holding mechanism using the loader arm for receiving and holdingthe old plate disengaged from plate lockup devices in thecircumferential surface of the plate cylinder of the printing unit; anew plate holding mechanism using the loader arm for holding and feedingthe new plate to the plate lockup devices in the circumferential surfaceof the plate cylinder of the second printing unit; an actuator meanscoupled between the frame and the loader arm for moving the loader armbetween a stored position, where the loader arm is separated from thecircumferential surface of the plate cylinder, and an actuationposition, where the loader arm is proximate to the circumferentialsurface of the plate cylinder; a plate replacement unit coupled to theframe integrating the old plate holding mechanism with the new plateholding mechanism so that the plate replacement unit operates both theold holding mechanism and then the new plate holding mechanism while theloader arm continuously maintains the actuation position, the platereplacement unit crossing a working space disposed between the frames ofthe at least adjacent printing units during movement of the loader armby the actuator means; at least one safety bar coupled to the frame ofthe printing press for crossing and closing the working space disposedbetween the frames of the at least adjacent printing units, the safetybar movable between an open position where an operator can enter theworking space and a closed position where the safety bar extends betweenthe at least two adjacent printing units to prevent the operator fromentering the working space; and a switch which inhibits the platereplacement unit from crossing the working space when the safety bar isin the open position.
 7. An apparatus according to claim 6, wherein theplate replacement unit moves upward away from the printing press whilethe loader arm is in the stored position, where the loader arm isseparated from the circumferential surface of the plate cylinder.